.is24-listing-content-box {
    display: flex;
    flex-flow: row wrap;
    justify-content: center;
    align-content: stretch;
}
.listing-wrapper {
    border: 1px solid #000000;
    margin: 10px;
}
@media all and (min-width: 601px) {
    .listing-wrapper {
        flex: 1 0 21%;
    }
}
@media all and (max-width: 600px) {
    .listing-wrapper {
        flex: 1 0 50%;
    }
}